Fairfield is a very small city located in the state of Illinois. With a population of 4,738 people and two associated neighborhoods, Fairfield is the 348th largest community in Illinois.

In terms of college education, the citizens of Fairfield rank slightly lower than the national average. 14.61% of adults 25 and older in Fairfield have a bachelor's degree or advanced degree, while 21.84% of adults have a 4-year degree or higher in the average American community.

The per capita income in Fairfield in 2022 was $33,524, which is middle income relative to Illinois and the nation. This equates to an annual income of $134,096 for a family of four. However, Fairfield contains both very wealthy and poor people as well.

The people who call Fairfield home describe themselves as belonging to a variety of racial and ethnic groups. The greatest number of Fairfield residents report their race to be White, followed by Asian. Important ancestries of people in Fairfield include German, English, Irish, Scottish, and Swedish.

The most common language spoken in Fairfield is English. Other important languages spoken here include Spanish and Polish.